Process for the manufacture of unsaturated aldehydes



June 1941- M. GALLAGHER EI'AL 2.245582 PROCESS FOR THE MANUFACTURE OF UNSATUR ATED ALDEHYDES Filed Sept. 28, 1938 F ig. 1.

3mm MILTON GALLAGHER RUDOLPH LEONARD HASCHE EQMM'J J W FORMALDEHYDE VAPOR/Z5)? ACETALDEHYDE 31 ACfmLDff/Ypf FORMAtDfl/YDE H547 EXC' HANGER VAPORIZER Patented June 17, 1941 2.24am H 'raoonss won me momma or uuss'ruas'mn mums Milton Gallagher, Louisville, K! and Rudolph Leonard Hnsche, Klngsport, '1enn., assignors to Eastman Kodak min, Rochester, N. Y., a corporation of New Jersey Application September 2a, 1938, Serial No. 232,180

(01. zoo-s01) and the hydrogenation products of both the aforementioned simple and substituted unsaturated aldehydes as well as other derivatives thereof.

The unsaturated aliphatic aldehydes are characterized by'including a double bond ,in their The unsaturated aldehyde,

carbon atom chain. acrolein, also referred to as acrylic aldehyde,

with which this invention is particularly concerned, has the formula: CH2=CH.CHO.'

This application is a continuation in part of our allowed application Serial No. 88,821, filed July 3, 1936.

Unsaturated aliphatic aldehydes and, in particular, acrolein have a number of uses. As indicated, these organic compounds may be converted to other chemical products. For example, acrolein may be converted to propionic aldehyde in accordance with the procedure set forth in our .copending application Serial No. 88,822 entitled "Improved method for the manufacture of propionic aldehyde, now Patent No. 2,150,158.

While liquid phase processes, known as aldol condensation have been carried out, wherein a single aldehyde combines with itself, and are quite well known, apparently few, if any, methods have been developed for the more or less direct manufacture of the unsaturated aldehydes and in particular unsaturated aldehydes containing an odd number of carbon atoms, with which the present invention is'concerned. Prior to our inventionthe manufacture of higher aldehyd'es has been confined in a number of instances, as pointed. out, to liquid phase operations or costly raw materials have been required.- In the instance of acrolein, prior to our invention,

acrolein has been manufactured by dehydrating glycerin (see for example Beilstein).

We have found a new method for the manufacture of unsaturated aliphatic aldehydes, and in particular unsaturated aldehydes containing an odd number of carbon atoms in the molecule such as acrolein, which is superior in a number of respects to processes previously employed in the manufacture of aldehydes.

Although our process may in some respects be considered essentially a condensation reaction, splitting off .water with formation of an unsaturated aldehyde, it may be contrasted with and differentiated from prior processes of condensatlon in a number of respects. For example, a single aldehyde, such as acetaldehyde, has 'been caused to combine with itself to form an hydroxy-aldehyde (aldol) which is later decomposed -by heat to drive of! water, resulting in crotonaldehyde. I

We have found an eflilcient and highly desirable procedure wherein at least two different aldehydes may be caused to combine'to produce an unsaturated aldehyde containing a number of carbon atoms equal to the sum of two aldehyde reactants.

It will be noted that prior art attempts to react two different aldehydes, have not resulted in the production of unsaturated aldehydes, but have either failed outright orresulted in the production of some other compound such as, for example, penta-erythritolfrom formaldehyde and acetaldehyde.

This invention has for an object to provide a process for the combination of two different aliphatic aldehydes to produce an aliphatic aldehyde containing a number of carbon atoms equal to the sum of the two aldehyde reactants. Another object is to provide a process for the production of unsaturated aliphatic aldehydes containing an odd number of canbon atoms in the molecule. A further object is to provide a process for reacting two different aldehydes in the vapor phase.

A further object is to provide a process for the reaction of the one carbon aldehyde, formaldehyde, with another aldehyde. Another object is to provide a process for reacting formaldehyde (formalin) or other source thereof,

. with one or more aldehydes such as acetaldehyde,

proplonaldehyde and butyraldehyde. Still anotherobject is to provide a vapor phase catalyst process for the production of unsaturated aliphatic aldehydes. Another object is to provide a simple and efficient process for the production of unsaturated aliphatic aldehydes which operate readily 0n commercially available raw materials. Still another object is to provide a catalytic process for the-reaction of aliphatic aldehydes containing a different number of carbon'atoms in the molecule. A still further object is to provide a process particularly adapted for the production of unsaturated aliphatic aldehydes such as acrolein, a-methacrolein, a-ethacroleln and the like. Another object is to provide a vapor phase catalytic process for the production of acrolein and substituted acroleins.

Still another object is to provide catalysts and catalyst supports for process involving the reaction of aldehydes containing a different numberv cally reacting at least two aliphatic aldehydes having a different number of carbon atoms in the molecule. In accordance with our preferred procedure, we have found that highly desirable results may be obtained by catalytically reacting formaldehyde and acetaldehyde (or other aldehyde) in accordance with the procedure set forth herein.

For further details concerning our new process and apparatus and a more complete understanding of our invention, reference is made to the accompanying drawing which forms a part of the present application. .In the accompanying drawing, in which like reference characters refer to like parts,

Fig. 1 is a diagrammaticv side elevation showing an apparatus set-up for practicing our new process.

Fig. 2 is a semi-diagrammatic side elevation of a modified apparatus for carrying out our new process. In both figures certain parts of the apparatus have been shown on section or in exaggerated scale for clarity.-

In Fig. 1, 2 represents a feed tank for one of the aldehydes. The tank is connected by conduit 2 through a rotameter 4 or other suitable device to vaporizer 8. Vaporizer 6 is connected by conheaters, boilers or vaporizers in the system will include jackets or other temperature controlling means as at l8, I! or [8 for the purpose of regulating the temperature of the respective containers. In the apparatus shown in Fig. 1 this would be done by injection of heating or cooling fluids in the jackets as the situation required.

The mixing valve or mixing chamber 8 may be connected by conduit is through a heat exchanger 20 to a catalyst chamber 2|. The catalyst chamber comprlses'the catalyst container 22 fllled with catalysts. This catalyst may be retained by screens or other means as at 23 and 24. The chamber is enclosed in a temperature controlling jacket 26. This jacket may be heated by steam, hot oil, molten chemicals, electric heat or in some other suitable manner or cooling fluids may be introduced if necessary. Another jacket 29 may be provided around the catalyst chamber so that the incoming mixture may be passed in heat exchange relationship with the catalyst bed.

While we have described the above type catalyst chamber, other types of catalyzers may be employed.

Catalyzer 2! is joined to condenser 21 by conduit 25. This condenser may be of the usual construction. A valve. draw-oi! 28 is provided in order that the condensate may be withdrawn from the condenser for other use or to storage.

Fig. 2 discloses a catalytic unit for carrying out our process somewhat differently. The unit of Fig. 2'is quite similar to the unit described under to condenser or other treatment.

Fig. 1. A feed tank II is provided for one of the components. This tank is connected by conduit 48 to the mixing point II.

Another feeding device ii is provided for the other component. Conduit 41 connects this device with the mixing point 38. The conduit 44 leads from the mixing point to a vaporizer or flashing apparatus 32. Or, in place of the two tanks ii and I, the two diiferent aldehydes may be premixed in the desired proportions and fed to the vaporizing or flashing device.

The apparatus 32 may include heating elements 33 upon which a mixture of aldehydes may be sprayed through 34. Vapors from unit 32 pass through conduit 31 to catalyst unit IO.

Catalyst uni-t It is heated or cooled as necessary by means of temperature controlling .coil 4|. The outside unit is insulated as at 42. Also, if desired.

the line 31 may be heated. The catalyst unit includes a charge of catalyst 43. Valved conduit 44 is provided for withdrawing the reaction products The catalyst unit is equipped with a thermometer well 4| whereby the temperature inthe interior of the catalyst may be measured. Also, as described with respect to Fig. 1, the incoming mixture may be caused to pass down the outside of the catalyst chamber, thereby absorbing heat before entering the catalyst chamber.

As already indicated, catalyst chambers 22 or 43 are fllled with the catalyst. A number of catalysts have been found to be satisfactory. Silica or alumina gel, as such, are satisfactory catalysts. However, the action of these materials may be improved by impregnating them or mixing therewith additional materials, such as sodium acetate, magnesium acetate, cadmium acetate, thoria, thorium oxide, molybdenum oxide or cobalt metal. While the above catalysts are satisfactory, our invention is not limited to these catalysts or catalyst supports. For example, a suitable catalyst for carrying out our process is magnesia supporting about 2-10% of metallic cobalt. Or magnesia ture conditions under which any particular cata-.

lyst will operate in our process may vary somewhat. Temperatures between about 200-400 C. appear to be satisfactory, and within this range the range of about 290 C. to 300 C. appears preferable in many instances.

In more detail, there are a number of other catalysts which have been employed and which function satisfactorily in our process. Among these other catalysts, the following may be mentioned:

The following materials were tried in an amount equal to 2.5% of the weight of the support: W0: and V205.

Five per cent of catalytic materials were used in the following cases: Formates of Zn, Mg, Cd, Hg, Ca, Ba, Cu, Ni++, Mn++, and Co++. The following acetates were used at 5%: Zn, Mg, Cd, Hg, Ba. Ca, Cu, Ni++, Fe++, Mn++, and Sr.

Five per cent of the following propionates were examined: Mg, Cd, Ca, Co++, Ni++, Ba, Cd and Zn.

The following were also used at 5%: Cami-1):, Mg oxalate, MgSO4, Mg(NOs)a, MgClr, MgCrO4, Tl(NOa) 4, NarCOr and Na(OAc).

Ten per cent of the following was used: Acetates of Mg, Mn++, Cd, Ba and Na, M001. thallium sulfate, (NHO: CI'2O1, Na:PO4, NaCl, NaHAsOr, NaBOa, NazB4O1, NSII'IPO, NaHaPO4, (NHOzMOOl, KCl, Be(NOa)z, Zr(NO:)4, Cr niphomolybdic acid andTh(NC:)4.

- .Twenty per cent of the following Mg804, Mg(OAc)z, MgCla,.M'g(NO a)a,1Co(NOa):, Ni( NOs)a, and NazCOs,

phosphotungstlc acid, uranyl nitrate, phoswas tried:

- Fifty per cent of Mg(OAc) was employed.

, 0.45 to 2.0% ofthe following were tested: MBQQAQ) a, F8203, Thor, Th(NO3) 4, K2003, metal 504, 2, .WO:, .Al(OH) 3, Cl'(OH):, BiCla, AlCla,

HgCNa, KaClO4, AllOAC) a, MBNASOO a, V205, Zr(NO:) 4, KaCOa and Th(NOs) 4 The following combinations of materials were tried as catalysts:

' MgCrOH-Cd (OAc) 2 A number of combination catalysts of MgO were prepared with at least one of the following materials: C0, Ba(OH):, F6203, HaPO4, ThOz, V205, W03, CB(NO3) 2, A80, Cd, Ag, Cu, C0.

The aforementioned catalysts were prepared by the following methods:

A. To 100 g. of silica gel was added an aq. acid solution prepared by adding cc. of strong acetic acid to 35 cc. of water, followed by gentle warming and the addition of 10 g. of ZnO, MgO, NiCOs, CdO or any other basic oxide or carbonate or hydroxide of the desired metal. Any excess liquid was removed by heating either with or without reduced pressure.

B. To 100 cc. of silica gel treated as above was added 10 g. H2804 diluted to 30 cc. with water. By this procedure the above acetates were combination catalysts comprising supports such. as gels, charcoal. magnesia. or the-like. impregnated or mlxedwith the various metals and metal salts specified, we sub-generically designated as impregna or "mixed dehydrating catalysts."

The operation of-our..new process and upwatus may be better understood by reference to the following examples which are setforth merely for the purpose of illustration. The following example is described as carriedout in the apparatus of Fig. 2.

The container 3i was filled with'a relatively pure liquid acetaldehyde. The acetaldehyde was permitted to flow to the mixing point II. Container 3' was filled with formalin, and this material was permitted to flow through conduit 41.

" The desired amount of acetaldehyde was mixed pletely converted to the corresponding sulfates precipitated directly on or within the pores of the gel. C. To 100 cc. of silica gel was added 10 g. HzSOi to which had been added 25 cc. H2O. To

The other catalysts described above may be prepared by the same general steps A, B, C already set forth. It is to be understood that while in the process examples sulphuric acid and other such specific agents have been described, other inorganic and organic acids or chemicals may be employed. For example, in place of the sulphuric acid, phosphoric could be employed.

While in the above examples in many instances the impregnating or mixing metal or metal salts was employed in amounts from .45% to 5 or 10%. it will be observed that amounts as high as were employed. Therefore, while we prefer a base impregnated or mixed with a minor proportion of a metal or metal salt, we do not wish to be restricted to these embodiments inasmuch as the proportions may be varied. We have also found that the silica gel and alumina gel may be mixed in varying proportions. For convenience, we designate our catalyst generically as dehydrating catalysts. The comcial acetaldehyde.

has a boiling point of about21 C. it may be dewith formalin at SI. This mixture was conducted through conduit ll into flashing apparatus l2. The mixture of acetaldehyde and formalin flowing'from 34 over heating means 33 vaporizes and was conducted through conduit 31 to catalyst unit 39.

The catalyst unit had been heated and during the reaction was maintained in a heated conditionby means of an electrical heating coil ll During a run of about six hours, approximately 101.3 grams of acetaldehyde and approximately 84 grams of formaldehyde fed, as formalin containing approximately 35% formaldehyde by weight were fed to the catalyst unit. The catalyst chamber, which was filled with one of the aforementioned catalysts, was held at about 285 C. by electrical heating. It is highly desirable that a temperature above 225 C. and preferably above 250 C., be employed. After a period of operation, which may be from 12 to 24 hours,

the catalyst may be regenerated.

It is also preferred to employ excess acetaldehyde (orother aldehyde higher than formaldehyde) in carrying out our reaction. By this procedure substantially all the formaldehyde is converted. This is also advantageous because it ,minimizes any difliculties of separating formaldehyde from the reaction products.

The acrolein containing materials were drawn off at 44, where the acrolein could be recovered treatment resulted'in a yield of approximately 51.8 grams of propionic aldehyde. This yield of propionic aldehyde indicates that a satisfactory yield of acrolein was obtained in the preceding step, inasmuch as hydrogen reacts with acrolein in accordance with the following reactions:

Acrolein Hydrogen Propionic aldehyde The following example is described with respect to Fig. 1. Tank 2 was filled with commer- Inasmuch as acetaldehyde sirable to circulate a cooling medium in jacket l6 to preventvolatilization of the aldehyde. In place of the cooling jacket it is, of course, apparcalcium carbide, cracking hydrocarbons or the decomposition of hydrocarbons in an electric arc.

The acetaldehyde may also be obtained from ethyl alcohol.

Formaldehyde (or materials containing formaldehyde) is placed in container 0. This container may be heated or cooled or otherwise acted upon dependent upon the particular formaldehyde material.

Relatively pure formaldehyde boils at approximately 21 C.- Formalin, which contains around 40% of formaldehyde, the remainder being principally methyl alcohol and water, is an easier; source of formaldehyde to work with. Also formalin is readily available commercially. We have found that the methyl alcohol content of formalin or other sources of formaldehyde does not interfere with our process. Solid paraformaldehyde may be employed. It is, therefore, apparent that our invention embraces vari-- ous sources of formaldehyde. We also contemplate the added steps of converting methyl alcohol into formalin and feeding theresultant reaction mixture through conduits H and I4.

In the example under description the formaldehyde materials were fed through rotameter l2 into the formaldehyde boiler II. The evolved vapors containing formaldehyde were conducted through conduit l4 to'the mixing point I.

From 8 the vapors containing formaldehyde and acetaldehyde with or without water, methyl covered as such and employed. or. as described with respect to-the preceding example, the aerolein may be converted to diflerent chemical compounds by hydrogenation or other treatment. Excellent yields of acrolein were obtained.

The above examples are merely illustrations of conditions for carrying out-ourprocess. The reaction conditions may be-varied and theabove examplesarenottobeconstruedaslimitingour invention. For example. the-moleratio of acetaldehyde to formaldehyde. while. generally kept within the'rangeof from 5-0.5 may be varied outside of these limits. The high ratio is desirable because the yield based on formaldehyde is smaller than the yield based on acetaldehyde, and we have found that a more-complete utilization of the formaldehyde could be obtained by usingti a higher formaldehyde to acetaldehyde re 0.

The use of excess acetaldehyde has other advantages, as indicated above.

The space velocities for the formation of acrolein may vary according to conditions and reaction equipment. We have found a range from 200-3000 to be suitable for carrying out our reaction. We may define "space velocity" as cubic feet of reactants fed per cubic foot catalyst per hour,-volumes of reactant materials measured at temperatures and pressures of reaction. As already indicated, the temperature range may vary from about 200 C. to 400 C. While we prefer to carry out the reaction under atmospheric conditions, it is possible to carry out the reaction under either higher or lower pressures.

Further examples illustrating the operation of our process may be observed from the following runs in tabulated form:

alcohol and the like, pass into and through catalyst 22. This catalyst, comprising either silica or alumina gel, was heated to approximately 290 C. to 300 C.

The following reaction apparently took place:

Formal- Acetalfi-Hydroxy dchyde dehyde propionaldehyde O OH H 0 C1110 CHsC e Cir-HC --e Acrolein Water CHs=CHC H 0- The vapors from the catalyst chamber coming off at 25 are passed through cooling device 21.

"At 20 acrolein containing some water, unreacted formaldehyde and acetaldehyde may be withdrawn. "The unreacted components may be separated and recirculated if desired.

As indicated above, the acrolein may be re- Our novel,procedure described herein represents a particularly satisfactory method for the manufacture of unsaturated aliphatic aldehydes containing an odd number of carbon atoms.

' Our preferred embodiment for the manufacture of acrolein permits the utilization of materials, such as formalin and acetaldehyde.

While our process is particularly adapted for the preparation of unsaturated aliphatic aldehydes as described in the above examples, our invention has wider applications and embraces similar procedure for the formation of other such products. an example of the formation of an unsaturated aldehyde with an even numberof carbon atoms is the reaction between formaldehyde and propionaldehyde to form a methacrylic-aldehyde.

It will be observed that by our process of reacting with formaldehyde, aldehydes of higher molecular weight than acetaldehyde, there may be obtained an alkyl group in the alpha position.

Such a-substituted type of compound has value in synthetic resin production and other similar uses. For a further example, formaldehyde combines'with normal butyraldehyde'to form a-ethacrolein in accordance with the following equation: N C H form any of the substituted acroleins in which we may be interested.

This reaction of formaldehyde with other aldehydes higher than acetaldehyde goes with greater ease and with higher yields than produced in the manufacture of acrolein by the aforedescribed reaction of formaldehyde with acetaldehyde. The catalyst does not become foul or lose its activity to any great degree even with extensive use in these processes for reacting formaldehyde with 3-carbon atom, 4-carbon atom or higher aldehydes.

Our process does not require the utilization of high pressures which is believed to be unusual for a process of this type. Our process is also particularly desirable from the standpoint that any by-products produced are few in number and-in relatively small quantities when our process is properly employed. Any unreacted components may be reutilized by circulation through the system.

It will be understood that our apparatus will be constructed of suitable materials and that proper precautions for preventing heat losses and leakage will be observed. We find that many of the parts of our apparatus may be constructed of a steel containing about 16-23% chromium, about 7%20% nickel and the balance substantially iron. This steel preferably has a content of carbon of about 6% or less. The steel may also contain small amounts of copper, silicon, molybdenum and tungsten. v

The term "rotameter" as employed herein refers to liquid measuring devices.

It is, therefore, apparent that while we have described our inventionin some detail, there are many changes that may be made therein without departing from the spirit of the invention.

What we claim is:

1. A chemical process which comprises forming a vapor containing acetaldehyde and formaldehyde, subjecting at least a part of the vapors to catalytic contact with an impregnated gel as a catalyst, maintained at a temperature between about 230 C. and 400 C.

2. A process for producing higher aliphatic aldehydes, which comprises reacting a mixture containing at least two difi'erent aliphatic aldehydes in the vapor phase and in contact with a catalyst essentially comprising a gel and from .45 to 50% of a metal salt catalyst, said catalyst being maintained at a temperature at least part of the time, whereby the reaction will take place under vapor phase conditions.

3. A process for producing higher aliphatic aldehydes, which comprises reacting a mixture containing at least two difierent aliphatic aldehydes in the vapor phase and in'contact with a catalyst essentially comprising silica gel and metal salt catalyst, said catalyst being maintained at a temperature at least part of the time, whereby the reaction will take place under vapor phase conditions.

4. A process for producing higher aliphatic aldehydes, which comprises react-ing a mixture containing at least two diflerent aliphatic aldehydes in the vapor phase and in contact with a solid catalyst essentially comprising alumina gel and a metal salt which is a catalyst, said catalyst being maintained at a temperature at'least part of Thuswehave discovered a process which will 7 least part of the time, whereby the reaction will the'time, whereby the reaction will takeplace under vapor phase conditions.

5. A process for producing higher aliphatic aldehydes, which comprises conducting a-mixture containing at least two difierent aliphatic aldehydes in the vapor phase into contact with a gel as a catalyst maintained at a temperature, at least part of the time whereby the reaction will take place under vapor phase conditions.

6. A process for the production of unsaturated aliphatic aldehydes, which comprises reacting formalin with another lower aliphatic aldehyde containing a greater number of carbon atoms, in the vapor phase and in the presence 01 a gel as a catalyst maintained at a temperature between about 200 C. and 400 C.

7. The chemical process which comprises reacting formaldehyde and acetaldehyde in the vapor phase and in the presence of a gel as a catalyst maintained at a temperature between about 250 C. and 400 C.

8. The chemical process for the production of a straight chain organic compound containing a double bond in the chain, which comprises passmg vapor containing formaldehyde and acetaldehyde into contact with a gel as a catalyst maintained at a temperature between about 250 C. and 325 C.

9. A process for the production of aliphatic aldehyde compounds containing an odd number of carbon atoms in the molecule, which comprises vaporizing a saturated lower aliphatic aldehyde containing a lesser number of carbon atoms than the aldehyde being produced, vaporizing another lower aldehyde different from the aforementioned aldehydes, mixing the aldehyde vapors and contacting the vaporous mixture with a gel as a catalyst maintained at a temperature sufflcient to cause reaction between the aldehyde vapors.

10. The chemical process which comprises vaporizing an aliphatic aldehyde containing less than four carbon atoms, vaporizing another and and recovering and separating the reaction products.

11. A process for producing higher aliphatic aldehydes, which comprises conducting a mixture containing at least two different aliphatic aldehydes in the vapor phase into contact with a silica gel as a catalyst maintained at a temperature, at

take place under vapor phase conditions.

I 12. A process for producing higher aliphatic aldehydes, which comprises conducting a mixture containing at least two different aliphatic aldehydes in the vapor phase into contact with an alumina gel as a catalyst maintained at a temperature, at least part of the time, whereby the reaction will take place under vapor phase conditions.

13. The substantially continuous single-step chemical process for the production of vinyl aldehydes, which comprises contacting vapors having therein as essential components formaldehyde and another aliphatic aldehyde, this other aldehyde, relative to the quantity of formaldehyde, being present in excess, with a solid non-caustic catalyst, said process being carried out at a temperature greater than 200 0., but less than 400 0., and at a space velocity between 300-2000.

14. The chemical process for the production of acroleins, which comprises passing a vapor containing formaldehyde and an excess of another lower aliphatic aldehyde in the contact with a solid non-caustic catalyst, maintained at a temperature between 250-400 C.

15. The substantially continuous single-step chemical process for the production of acroleins, which comprises contacting vapors having therein as essential components formaldehyde and another aliphatic aldehyde, this other aldehyde, relative to the quantity of formaldehyde, being present in excess, with a solid dehydrating catalyst, said process being carried out at a temperature greater than 200 0., but less than 400 0., and at a space velocity between 300-2000.

16. A process for producing unsaturated aliphatic aldehydes which comprises conducting a mixture containing at least two diflerent aliphatic aldehydes in the vapor phase into contact with a solid dehydrating catalyst maintained at a temperature, at least part or the time, whereby the reaction will take place under vapor phase conditions.

. MILTON GALLAGHER.

RUDOLPH LEONARD HASCHE. 

